The present invention concerns continuous-operation crushing machines of the type used to reduce the size of large pieces of material, most typically coal and sometimes pieces of rock contained in the chunks of coal. Conventionally, the crushing machine comprises a crushing roller which is rotated such that its periphery travels in the same direction as the conveyor which transport the material through the crushing machine. Typically, the crushing roller is mounted above the guide trough of the conveyor, spaced from the conveyor a certain distance so as to leave room into which the material to be crushed can enter.
Conventionally, such a crushing machine has a throughgoing shaft, the axial ends of which are journalled on the housing of the machine. The crushing roller is mounted on the shaft and is fitted with crushing implements. Because such mounting shaft is surrounded by the crushing roller, the distance between the crushing roller and the bottom of the conveying trough determines the maximum height of the endless body of material which can be fed through the crushing machine. If it is desired to increase this distance, to permit the machine to process a greater amount of material per unit time, then this requires that the crushing roller be raised, which in turn requires that the crushing-machine housing be lifted to a height greater than would otherwise be necessary.